Apparatus known for use to strip the contents of flexible, collapsible plastic containers and tubing are disclosed in U.S. Pat. Nos. 951,101 to Clarke, 1,352,425 to Bove, 1,460,204 to Maraffi, 1,470,534 to Keiper, 1,692,116 to Greist, 1,716,388 to Sherfy, 2,003,283 to Chatelain, 2,110,868 to Coates, 2,183,060 to Blake, 2,206,985 to Vogt, 2,542,678 to Keefer, 2,578,472 to Gunnarson, 2,876,934 to Brim, 3,197,072 to Dick, 3,263,862 to Tazzeo, 3,507,278 to Werding, 3,604,418 to Jones, 4,639,251 to Kirkland, 4,850,971 to Colvin and 5,118,011 to Kopp.
Among these known apparatus, the patents to Werding, Jones, Kirkland and Colvin disclose medical devices used with flexible fluid bags and tubing thereof.
In hospitals and medical facilities, it is known to use a pressure bag to strip fluid from an IV bag so that the fluid can be injected into a patient, i.e. subcutaneously, intramuscularly or intravenously. The conventional pressure bag resembles a donut shaped member with a centrally located hole into which a filled IV bag is disposed. The pressure bag is then inflated by, for example, repetitive squeezing of an air bulb, to reduce the size of the central hole and exert pressure against the IV bag. The fluid contained in the IV bag is accordingly stripped or expelled from the container through a catheter. When the IV bag has been emptied of the fluid contents, the pressure bag is deflated to remove the stripped container and to receive another filled IV bag. This process is laborious, time consuming and particularly uncomfortable for the individual inflating and deflating the pressure bag if a plurality of IV bags must be employed in, for instance, an emergency situation where a patient is to receive many units of blood, plasma, etc.
Another disadvantage is that the known pressure bag and the related medical devices must be manually reset to receive another IV bag for a subsequent stripping and infusion application.
In addition, known conventional IV pumps can strip a flexible container of parenteral fluid at a rate of approximately 1000 cc/hour, while the conventional pressure bags are more efficient and can strip the parenteral fluid at a rate of approximately 15,000 cc's/hour. In emergency situations, however, it is desirable to have an apparatus which strips the parenteral fluid from the IV bag at a still higher rate.
Moreover, the conventional pressure bag and related devices are not adapted to sense and monitor the pressure being exerted on the IV bag so that a determination can be made as to whether to increase, maintain or reduce the pressure on the IV bag. This is important because various IV fluids having different viscosities are used.
For example, among the devices used for dispensing fluids from IV bags, U.S. Pat. No. 3,507,278 to Werding discloses an apparatus for dispensing parenteral fluid, such as blood, and which includes a casing which forms a hermetic enclave into which compressed air is introduced via a valve. A flexible container with fluid is disposed within the casing and communicates with the outside of the enclave by a flexible tube. Compressed air introduced into the casing through the valve forces the fluid from the container through the tube.
U.S. Pat. No. 4,850,971 to Colvin discloses an infusion method and means which includes a tray for holding an IV bag. The tray has sides formed with longitudinal slots. A drum has cocking handles at each end which extend through a corresponding one of the slots to move from one end of the tray to the opposite end. A coil spring is mounted to the drum to pull the drum against the bag to pressure the contents therefrom.
U.S. Pat. No. 3,604,418 to Jones discloses an apparatus for stripping fluid from flexible plastic tubing, such as tubing used with blood collecting devices. The apparatus includes hinged portions, each of which is provided with a roller to be in close proximity to one another yet permit the flexible plastic tubing to pass therebetween and be stripped of any fluid remaining in the tubing. The stripped fluid is returned to the fluid dispensing bag.
None of the devices discussed above provide an infusion apparatus for an IV bag which is adapted to force parenteral fluid from the IV bag under pressure between a pair of rollers and sense the pressure to determine whether the pressure should be increased, maintained or reduced with respect to the particular infusion application. None of the devices are adapted to be automatically reset to facilitate removal of an empty IV bag and mounting of a filled IV bag for the next infusion application.